In many approaches to production of fuels, nutraceuticals and other useful products by growth and conversion of algae products, a growth stage of alga in a controlled environment must be evaluated, for purposes of estimation of lipid contant and for other metrics. It is often very inaccurate to estimate alga growth stage based only on time of growth, because of variations in important environmental parameters during different growth cycles.
What is needed is a more accurate approach that does not depend solely on time of growth and that implicitly factors in the variable environmental parameters and provides a useful error estimate for alga growth stage. Preferably, the approach should implicitly or explicitly take account of the environmental history of growth of the alga.